Per favore potete tradurre inoltre questi “titoli” per farmi capire meglio:Police says: Maria, could have disappeared on Monday.Paulo could be deadPaulo could have been dead for monthsFinancier YY could have hidden most assets overseas

Sorry about the confusion regarding place and sex of patient but I just read the headline.

So to conclude what you are saying then is that the original headline states that the person in coma is likely to have suffered brain damage. It’s not such a big difference from could have possibly in this context since the Doctors must have some rather stromg reasons to suspect this and to tell the press about it.

But I do appreciate and understand the difference in nuance as described by you. Thanks to all of you..

The use of the conditional here does not refer to the degree of probability. It means "going by what people say". When a person is arrested on suspicion of a crime, they often say, for example, "sarebbe il capo di un gruppo terroristico". It means "he is said/alleged to be...". It's not the same as "might be" or "is likely to be".